Method of producing cocrystallized vanadium, titanium, and aluminum halides



United States Patent METHOD OF PRODUCING COCRYSTALLIZED VA- IIYIBDISUM, TITANIUM, AND ALUMINUM HA- Erik Tornqvist, Roselle, N..l., and Perry A. Argahright,

Englewood, Colo., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application Feb. 20, 1963, Ser. No. 260,081, which is a division of application Ser. No. 827,710, July 17, 1959, now Patent No. 3,139,419. Divided and this application May 24., 1965, Ser. No. 458,398

8 Claims. (Cl. 252442) This invention relates to an improved catalyst system utilizing improved catalyst components for the low pressure polymerization of alpha olefins; the present application is a division of SN. 260,081, filed Feb. 20, 1963 and now U.S. Patent 3,223,651, which is a division of SN. 827,710, now U.S. Patent No. 3,139,419, filed on July 17, 1959. More particularly it relates to these components containing co-crystallized reduced titanium and vanadium halides with co-crystallized aluminum trihalides, their preferred method of preparation and their use in obtaining polymer products of reduced Bell Brittleness temperature.

The low pressure polymerization of alpha olefins with catalyst ssytems made up of a partially reduced, heavy, transition metal compound and a reducing metal-containing compound to high density, often isotactic, high molecular weight, solid, relatively linear products has been assuming ever increasing importance and is now Well known.

For the purpose of convenience details of the low pressure catalytic process and the products obtained thereby are presented below, although it should be realized that these by themselves constitute no part of this invention.

The alpha olefinic feeds utilized in polymerization and copolymerization include C -C olefins, e.g., ethylene, propylene, butene-l, hexene-l, etc., with ethylene and propylene preferred. The process is described in the literature, e.g., see U.K. Patent 810,023 and Scientific American, September 1957, pages 98 et seq.

In the process the polymers are prepared by polymerizing the monomer with the aid of certain polymerization catalysts. The catalysts are solid, insoluble, reaction products obtained by partially reducing a heavy metal com pound of a Group IV-B, V-B, and VL-B metal of the Periodic System, such as vanadium tetrachloride, or a titanium halide, e.g., TiCl TiBr etc., preferably with metallic aluminum. The preferred catalyst of this type is usually prepared by reducing .1 mole of titanium tetrahalide, usually tetrachloride, with about one-third mole of aluminum to give a material corresponding to TiCl -0.33

A1Cl thus containing co-crystallized AlCl (For further details see copending U.S. application S.N. 578,198, filed Apr. 6, 1956 and SN. 766,376, filed Oct. 19, 1958.) The product is then activated with an aluminum alkyl compound corresponding to the formula RR'AlX. In this formula R,R' and X preferably are alkyl groups of 2 to 8 carbon atoms, although X may'alternatively be hydrogen or a halogen, notably chlorine. Typical examples of the aluminum alkyl compounds are aluminum triethyl, diethyl aluminum chloride, aluminum triisobutyl, etc.

- The monomer is then contacted with the resulting catalyst in the presence of a hydrocarbon solvent such as isopentane, n-heptane, xylene, etc. The polymerization is conveniently effected at temperatures of about 0 to 100 C. and pressures ranging from about 0 to 500 p.s.i.g., usually 0 to 100 p.s.i.g. The catalyst concentration in the polymerization zone is preferably in the range of about 0.1 to 0.5 Wt. percent based on total liquid and the polymer product concentration in the polymerization zone is preferably kept between about 2 to 15% based on total contents so as to allow easy handling of the polymerized mixture. The proper polymer concentration can be obtained by having enough of the inert diluent present, or by stopping the polymerization before: the full polymerization capacity of the catalyst has been utilized, or before 100% conversion of the monomer has been realized.

When the desired degree of polymerization has been reached, a C to C alkanol such as methanol or isopropyl alcohol desirably in combination with a chelating agent such as acetylacetone is normally added to the reaction mixture for the purpose of dissolving and reactivating the catalyst, removing some catalyst residues from the polymer and for precipitating the crystalline polymer product from solution.

The polymers produced have number average molecular weights in the range of about 100,000 to 300,000 or even as high as 3,000,000 as determined by the intrinsic viscosity method using the I. Harris correlation (J. Polymer Science, 8, 361 (1952)). The polymers can have a high degree of crystallinity and a low solubility in nheptane.

It is to be understood that the term low pressure polymer as used herein connotes material prepared in the indicated manner and includes homoand copolymers.

One of the problems encountered in the process is excessive low temperature polymer brittleness, particularly in the case of polypropylene, which limits the utility of the product as a packaging material for frozen foods, wire and cable insulation, plastic pipes, etc. Low temperature brittleness is commonly measured by the Bell Brittleness Temperature Test (ASTM Test D-746).

It has now been found that utilizing as the heavy transition metal halide component a co-crystallized titanium vanadium and aluminum component corresponding substantially to the formula yTiX -(1y) VX -0.33 A1X wherein X is halogen and y is .50 to .97, in the catalyst system, gives extremely active catalysts and polymer products of reduced Bell Brittleness temperature.

It is especially surprising that the catalyst components of this invention are as effective as stated in that components containing the 3 metals which are not co-crystallized are substantially less effective in catalysis. Furthermore, the results obtained with the use of the catalysts of this invention are superior to those obtained with separate amounts of titanium and vanadium halides. Thus, a synergistic eifect is produced by the co-crystallized compounds.

In the formula of the improved components of this invention shown above, X is a halogen, preferably chlorine or bromine, and y is .50 to .97, preferably .67 to .90. Data have demonstrated that figures outside this range are not as etficacious.

The catalyst components are activated as previously stated in the same manner as utilized in the art. Molecular ratio of the aluminum alkyl compound to co-crystallizecl component is in the range of 0.5 to 10.

Since it is necessary that a co-erystallized system be utilized herein, the method of preparation is important These components can thus be prepared generally by the slurry or bomb technique.

In the slurry technique, in order to prepare the mate: rials of this invention the titanium and vanadium components, e.g., titanium tetrachloride and vanadium tetrachloride, are added as such or in an aromatic diluent to aluminum powder in an aromatic diluent. The amounts of the components are indicated from the formula and the resultant slurry maintained at a minimum temperature of about C. The reaction is. carried out for a 3 time sufiicient to produce substantially complete reaction of the aluminum with the titanium tetrachloride and vanadium tetrachloride so as to obtain the desired product co-crystallized with aluminum chloride. The re- 4 percent VCl4. The temperature was then increased to refluxing, about 112 C., causing complete reduction of the transition metal halides to their trivalent form. The reduced material was recovered by filtration after refluxaction time is not critical but will generally be in the 5 ing for 3-4 hours. It was thoroughly washed with n-heprange of 0.5 to 20 hours, preferably 1 to 5 hours. tane, dried in vacuo below 100 C. and milled with The powdered aluminum metal used in the process is steel balls for 3 days. These systems are designated as finely divided ball-milled or atomized aluminum powder Al TiV in Table I. such as Alcoa Grade 123. In general, the particle size In the second series of reduction experiments the tranof the aluminum metal is in the range of 1-100 microns. l0 sition metal mixture (1 mole in 200 ml. toluene) was The diluents used for the reduction are aromatic hyadded to the aluminum slurried in 300 ml. of refluxing drocarbons having melting points below about C. toluene. Under these conditions both the TiCl4 and VCl4 or mixtures of such diluents with inert aliphatic diluents were reduced almost instantaneously yielding a co-crystallike n-octane, n-decane, etc. Examples of suitable diluents lized product. These components are designated as are benzene, toluene, xylene, mesitylene, pseudocumene, Ti-V Al in Table I. ethylbenzene, cymene, tetraline, Decalin, chlorobenzene, The components prepared in the manner stated plus o-dichlorobenzene, orthochlorotoluene and the like. one component made by aluminum reduction of TiCl4 Benzene used at a pressure high enough to allow the were activated with 2 moles of aluminum triethyl and reduction to take place above about 110 C. is particuutilized in the polymerization of propylene at atmospheric larly preferred since this diluent does not form resinous pressure using a reaction time of 2 hours at about 75 materials or other decomposition products during the C. and in xylene diluent. Further details and results are reduction reaction. given in Table I below.

TABLE I Cat. Mole Cat.Etf., [1 b Mn l0- Tensile (1 Prep. Percent V g./g. 1

Ti- Al c 265 3. 39 260 4, 240 0.8975

Ti-V- A1 5 316 3.50 270 3,965 0. 8964 liV- Al 10 401 2. 57 155 4, 210 0. 8986 iiV- Al 10 405 2. 76 165 3, 865 0. 8969 Al- Ti-V 5 322 2, 92 195 4, 030 0. 8980 Al- 'Ii-V 10 219 2. 66 162 4, 200 0. 8969 Al Ii-V 10 223 2. 81 185 3, 675 0. 8967 e Calculated on the solid catalyst component.

b Intrinsic viscosity.

The co-crystallized product is present in the aromatic diluent in finely divided crystalline form. It can then be activated directly with an aluminum alkyl compound. Alternatively it can be separated from the reaction mixture, such as by filtering, preferably at or close to the temperature of the reduction, then pebble-milled or preferably ball-milled when dry to produce a highly active catalyst component, and thereafter slurried in a hydrocarbon diluent and treated with an aluminum alkyl compound.

The beforementioned method of preparation is important since either the addition of aluminum to the titanium-vanadium salts in the aromatic diluent or operating below the temperature stated results in preferential reduction of the vanadium compound and the failure to obtain a true co-crystallized three-component system. This failure is apparent in the lesser activity of the catalyst system.

Alternatively, the co-crystallized components of this invention can be obtained by reacting the necessary materials, e.g., aluminum+titanium and vanadium halides in a bomb, in the absence of a diluent, at about 200400 C., preferably 220300 C., and using reaction times in the order of 0.5 to 10 hours, preferably 1-6 hours.

This invention and its advantages will be better understood by reference to the following examples.

Example 1 Two samples of catalyst components were prepared. In the first, a mixture of TiCl4 and VCl4 containing one mole of transition metal halide was added to a 2 1. round bottomed flask containing 350 ml. toluene and equipped with stirrer, cooler, thermometer and addition funnel.-

The improved catalyst efficiencies of the co-crystallized component of this invention over the control (Ti- Al) and over the systems where true co-crystallization did not occur (Al- Ti-V)is apparent.

Example 2 An example similar to that of Example 1 was run except that a tricrystalline catalyst component was also prepared in a bomb refererd to below as the dry method.

The systems were employed for polymerizing propylene in exactly the same manner as in Example 1. The results are presented in Table II.

TABLE II Experiment Catalyst Polym. V Mole Catalyst Preparation Temp., 0. Percent Elf. g./g.

l G. polymer per g. 01' total catalyst.

1 A corresponding TiCl -OBB AlCl -catalyst gives g./g. under similar conditions. This table shows how the catalyst efiiciency increases with the incorporation of vanadium into the crystalline system but passes through a maximum and diminishes again with the exclusion of titanium. It also shows the increased catalyst efficiency with the true co-crystallized system as contrasted to those where such co-crystallization does not occur.

Example 3 Further details are presented below on the bomb preparation of the catalyst components of the invention P esS. These are presented in Table III.

5 TABLE HI PREPARATION OF ORYSTALLINE yTiO13(1 y) ing a titanium tetrahalide a vanadium tetrahalide, and

volt-0.33 A1013 CATALYST aluminum in amount sufficient to produce a product cor- Rocking Bomb] responding substantially to the formula where X is halogen and y is .50 to .97 which comprises: either, (a) reacting a titanium tetrahalide, a vanadium tetrahalide, and aluminum in the absence of diluent at a temperature of about 200 to 400 C.; or (b) adding a titanium tetrahalide and a vanadium tetrahalide to alumi- 0ompos1tion 0.5 Ti0l -O.5 0.67 Time-0.33 5

VCls-0.33 A1015 0130.33 A1013 Total Charge, g Reaction Conditions:

Maximum Temp. 0

of at least 80 C.

l iiiic i', g f 2. The process of claim 1 wherein the reaction occurs Color oflmduct in the absence of diluent, and the reaction time is about 1 The actual reaction time was much shorter as shown b the time- 05:10 hours. temperature relationsmp early in the reaction y a. The process of claim 1 wherein the reaction occurs 1 After washing with dry n-heptane, drying in vacuo and ball milling. 1n the presence of an aromatic diluent and the reaction Bwwmsh Purple time is about 05-10 hours.

Example 4 4. The process of claim 3 wherein the aromatic diluent is toluene.

The effect of incorporating vanadium into the co- 5. The process of claim 1 wherein the titanium halide crystallized catalyst system on the Bell Brittleness temis titanium tetrachloride and the vanadium halide is perature of polypropylene is shown in this example. The vanadium tetrachloride. catalyst components were prepared by either the slurry 6. The process of claim 2 wherein the titanium halide or bomb (dry technique). Further details are indicated is titanium tetrachloride and the vanadium halide is in Table IV below. vanadium tetrachloride.

TABLE IV.-yTiC1 -(1y)V0l -1/3 A101 CATALYSTS FOR PROPYLENE POLYMERIZATION [2.1 glass atm. batch unit; xylene; 2AlEt /(Ti-l-V) Ol /75 0.]

Mole Percent Catalyst Days Catalyst Molecular Tensile, Bell Brittle- Vanadium Preparation Ball EfliClGIlCY, WeightXlO- p.s.i. ness, I

Milled g./g./2 hrs.

0 Dry 4 190 105 4,540 65-80 0 Slurry (toluene) 3 115 260 4,400 65-80 do 3 175 160 4, 200 5501 These results demonstrate the marked decrease in Bell 7. The process of claim 3 wherein the titanium halide Brittleness temperature obtained by the incorporation of is titanium tetrachloride and the vanadium halide is vanadium into the co-crystallized catalyst system. The vanadium tetrachloride. diminution in catalyst efficiency and tensile strength as 8. The process of claim 4 wherein the titanium halide the vanadium exceeds the maximum permitted is also is titanium tetrachloride and the vanadium halide is apparent. vanadium tetrachloride.

The advantages of this invention will be apparent to those skilled in the art. Novel catalyst components of References Cited increased activity are made available and the properties UNITED STATES PATENTS oi the polymers produced thereby are improved.

It is also possible to replace the aluminum reducing 3,109,822 11/1963 man et a1 252-429 material with other metals such as Ti, Ga, In, provided 311281252 4/1964 Torllqvlst et a1 2- 9 the reaction conditions are properly modified to allow 3,218,266 11/1965 Ludlum 252-429 good co-crystallization of the titanium and vanadium FOREIGN PATENTS halides to take place.

799,850 8/1958 Great Britain.

It is to be understood that this invention is not limited 572,660 2/1958 Italy.

to the specific examples which have been offered merely as illustrations and that modifications may be made without departing from the spirit of the invention. DANIEL WYMAN P r "em Examine"- Whatisclai111edis= TOBIAS E. LEVOW, Examiner. 1. A process of preparing a co-crystallized tltanium, vanadium and aluminum catalyst component by react- J. G. LEVIT T, L. G. XIARHOS, Assistant Examiners.

num in an aromatic diluent and heating to a temperature 

1. A PROCESS OF PREPARING A CO-CRYSTALLIZED TITANIU, VANADIUM AND ALUMINUM CATALYST COMPONENT BY REACTING A TITANIUM TETRAHALIDE, A VANADIUM TETRAHALIDE, AND ALUMINUM IN AMOUNT SUFFICIENT TO PRODUCE A PRODUCT CORRESPONDING SUBSTANTIALLY TO THE FORMULA 